Ballard Monster Mash is from 6-8 p.m. Friday at the Ballard Community Center, 6020 28th Ave. NW. Wear your costume and dance to a DJ, make some crafts and eat tasty treats. Cost is $5 at the door, $4 ahead of time (register online at www.seattle.gov/parks using code 89436).

The annual Trick or Treating along Greenwood Avenue is from 12-3 p.m. Saturday. Participating businesses have an orange poster in their window, but most will have someone standing outside giving out candy to the masses. This is a hugely popular event, and there will be hundreds, possibly even thousands, of children walking around the neighborhood, so please be extra careful when driving.

The 3rd annual Halloween on Holman is set for 1-4 p.m. Saturday at Carkeek Plaza. Face painting, prizes, a DJ, and chair massages for weary grown-ups, plus trick-or-treating from neighborhood businesses. Please bring a can or two of food to donate.

The Phinney Neighborhood Association’s 14th annual Dia de los Muertos Festival is set for 6-9 p.m. on Friday, Nov. 2. It begins with a procession lead by Sound Wave (the Sounders’ band), and continues at the PNA with several performances, sugar skulls, a traditional altar for remembrances, Mexican hot chocolate, face painting, children’s activities by Polly Glot Tots, and more.

The community altar will be dedicated at 6:35 p.m. (Bring in your own items for the alter starting Oct. 31.) At 6:45 p.m., see performance by the students of PCPE, the Phinney Cooperativa Preescolar. Marco Cortes performs at 7 p.m.; Bailadores de Bronce performs at 7:50 p.m.; and the Tlalok Aztec Dancers perform at 8:15 p.m.

Made Sewing Studio at 8408 Greenwood Ave. N. is open for Halloween costume help from 3-7 p.m. Tuesday through Friday, and 11 a.m. to 6 p.m. Saturday and Sunday. Cost is $10 per hour. Made also has a Sewing Ninja Power Hour every Saturday. The three-hour stint is dedicated to making costumes. Cost is $40.